(1) Field of the Invention
The present invention relates to a process for producing an extraction chromatography resin.
(2) Description of the Prior Art
In the prior art, after adding an planned amount of extracting agent and adsorbent resin to a volatile organic solvent such as cyclohexane, the organic solvent is volatilized. In this process the resin impregnated with extracting agent is produced as an extraction chromatography resin.
Up to the present about 30 kinds of bidentate organic phosphorus compound as solvent extracting agent have been synthesized.
As a typical example there is DHDECMP (dihexyl-N,N-diethyl carbamoyl methyl phosphonate) (hereinafter called as "A agent") having the following structure: ##STR1## herein, R and R' are alkyl radicals, and ##STR2## are extraction functional radicals.
In the production of this solvent extracting agent, organic byproducts are produced and remain, even after purification. In particular an acidic organic phosphorus compound (hereinafter called as "B agent") as shown in the following structure: ##STR3## herein, R and R' are an alkyl radical, is open to question.
Besides the above mentioned extraction functional radicals, hydrogen atom of OH combined to P dissociates to become a cation exchanger.
Though also this cation exchanger acts as an extracting agent, because A agent and B agent are different in extraction mechanism, in case of separating two kinds of metal ion, the separation effect is deteriorated.
That is, in the prior art, a both A and B agents-loading chromatography resin has been produced, which, as shown in FIG. 1, shows almost the same behaviors when extracting trivalent americium and curium from a nitric acid solution.
In FIG. 1, abscissa represents concentration of nitric acid solution (M) and ordinate, distribution ratio (Kd). Mark .smallcircle. shows a datum of trivalent americium and .circle-solid. is of curium.